Using co2 filled balloons to purge the headspace? Practical?

[Ali01]

Hi

I don't have a keg or a co2 tank, and this time I'd like to dry hop my homebrew, I can use the magnets method, but I think at 20c, the hops will lose a lot of oils before fermentation is complete. Right?
I wanna know if it's possible to collect the CO2 during fermentation in a balloon, then use that co2 to purge the headspace after dry hopping, using this method:
I connect a small tube next to the blow off tube, cut by a value
I'll also connect a value in the middle of the blowoff tube, I will open this value after pitching
The idea is when fermentation starts, the generated co2 will push any o2 out of the carboy, after a few minutes of bubbling ,I will close this value, blocking the co2 from escaping, and then I'll open the value to the balloon, it'll fill the balloon, and when it's big enough, I'll close this value and open the blowoff value, after dry hopping, I'll open both values in order for the co2 from the balloon to push out the o2 in the headspace, will that work?

 

[Somesaymybeerisdrinkable]

You will probably need a mylar balloon since a rubber balloon would require greater pressure to hold CO2. The CO2 balloon would be useful if you could crash.

Some alternatives for removing O2 when dry hopping; dry hop before fermentation is complete, add some sugar with the hops so the yeast make the CO2, or add sodium or potassium metabisulfate (less than 1/2 campden table) for its redox effect.

The bigger risk of cold side oxygen will be during packing, if you are not doing a closed transfer to a purged keg you will pick up some O2.

For what it's worth I don't purge the headspace when dry hopping because I don't want to move my CO2 tank. I add SMB with the hops for insurance, but manly I try to keep my beer cold once it is finished.

 

[Ali01]

You will probably need a mylar balloon since a rubber balloon would require greater pressure to hold CO2. The CO2 balloon would be useful if you could crash.

Some alternatives for removing O2 when dry hopping; dry hop before fermentation is complete, add some sugar with the hops so the yeast make the CO2, or add sodium or potassium metabisulfate (less than 1/2 campden table) for its redox effect.

The bigger risk of cold side oxygen will be during packing, if you are not doing a closed transfer to a purged keg you will pick up some O2.

For what it's worth I don't purge the headspace when dry hopping because I don't want to move my CO2 tank. I add SMB with the hops for insurance, but manly I try to keep my beer cold once it is finished.

I have some potassium metabisulfate but I'm afraid that might stop yeast activity and cause bottle conditioning issues
Also, I've had that you should dry hop when fermentation is over so that the aroma isn't taken away by the gas

 

[Jeroen79]

Collecting CO2 in a balloon is good for coldcrashing, but i don't see how you can push out oxygen with it after dryhopping, what i do is just open it for a verry short time, and just also add a little sugar, that way new co2 will be generated to cover the beer.

 

[Somesaymybeerisdrinkable]

I have some potassium metabisulfate but I'm afraid that might stop yeast activity and cause bottle conditioning issues
Also, I've had that you should dry hop when fermentation is over so that the aroma isn't taken away by the gas

The amount of metabisulfite you need to add to 5 gallons of beer is measured in milligrams, which is not enough to harm the billions of yeast in the beer. I would bet you could ruin your beers flavor by adding too much KMB before you harm the yeast enough to stop carbonation. In the comments Scott Janish recommends 0.2 g per 5 gallon batch.

Fermentation can drive off aromatics but if you are on the tail end it should be minimal. It does not take much fermentation to purge the headspace, assuming your fermenter has 20% headspace one S.G. point drop will produce about 3 headspace volumes of CO2. One downside of this is the hops might have a longer contact time than you want.

 

[tracer bullet]

Just to be clear, if you use the magnets, the idea is that they keep the hops out of the beer until you are ready. You shouldn't lose much from them if they are in the head space.

The balloon idea should work. The idea makes sense - let it fill with CO2 during fermentation, and then after you dry hop (which might include opening the fermenter), squeeze the CO2 back out of it into the headspace. I can't say if it is "worth it" but yes it should work. The mylar suggestion is good (the shiny foil kid balloons).

 

[Ali01]

Just to be clear, if you use the magnets, the idea is that they keep the hops out of the beer until you are ready. You shouldn't lose much from them if they are in the head space.

The balloon idea should work. The idea makes sense - let it fill with CO2 during fermentation, and then after you dry hop (which might include opening the fermenter), squeeze the CO2 back out of it into the headspace. I can't say if it is "worth it" but yes it should work. The mylar suggestion is good (the shiny foil kid balloons).

I like the idea of magnets but I think the hops will lose too much oil before they are added, right? since they're not in the freezer anymore

 

[tracer bullet]

I like the idea of magnets but I think the hops will lose too much oil before they are added, right? since they're not in the freezer anymore

Well, I'd be interested to hear from others who know more. But here are a few thoughts:

* They are covered in CO2, so anything lost due to the presence of oxygen is not a problem
* We are talking about a few days, not a few months, so any loss that occurs should not be very high
* How much time did they already spend not frozen, before they got to your freezer, and has anything bad happened

I don't think they are losing oil, but yes they could be losing some of their flavors and smells. But I don't feel like it's enough to worry about.

In the end you can probably use whichever method is easier, and have similar results. Both of which are good things to be thinking about and will result in better beer!